Method of and apparatus for



E. PETTY June 8, 1937.

METHOD OF AND APPARATUS FOR` FILTERING HIGH VISCOSITY LIQUIDS 2 Sheets-Sheet l Filed Sept. 21, 1935 @QN IIY .InII

June 8, 1937. 4 E. PETTY` 2,082,847

METHOD OF AND APPARATUS FOR FILTERING HIGH VISGOSITY LIQUIDSl Filed Sept. 21, 1935 2 Sheetg-Sheet 2 A TTOR EY Patented June 8, 1937 iSTATES PATENT OFFICE .N

i' METHOD 0F AND APPARATUS FOR FLTER- ING HIGH VISCOSITY LIQUIDS Earl Petty, New York, N. Y., assignor to Alco Products; Incorporated, NewYork, N. Y., a corporation of Delaware Applicuon September 2l, 1933,Serlal No. 690,385 K My'invention" relates to a novelprocess and apparatus forv ltrationland more particularly to a filtration process wherein a low viscosity diluent is used to control the rate of ltration.

It is known in the art that liquids bearing.

finely divided solids in suspension, or colloids in solution, may be effectively ltered by means of apparatus such as that disclosed in Patents Numbers 1,690,537, 1,744,510, and 1,773,797, granted to H; S. Hele-Shaw. This type of filter comprises .a large number of superimposed discs of paper,

l novel method for increasingA the rate of filtration and clarifying of the Hele-Shaw type .filter units by lowering the viscosity of the liquid to be filtered by the addition of a proper amount o a low vviscosity diluent.

Another object of my invention is to provide a filtration system permitting of continuousoperation. a

Still another object of my invention is to provide a method of filtration in which the diluent is continuously, recovered 'and recycled in the system. i

A further object of my invention is to provide a multi-stage system qi filtration in which caking of the slurry formed is prevented. A

A" still further object of my invention is to make use of a diluent which will bring in addi- -tion the feature of not only low viscosity but also a low density of' the solution making separation eective, the separation being by a. combination of gravity and positive flltratlon"on decanted liquid. y g

A still further object of 'my invention `is to provide a filter chamber having a. baille system .Y

to prevent turbulence in the chamber as a result of the agitation of the slurry by recycling.

In general, my invention contemplates the adlmixing of a liqueed gas having a viscosity of .003

poise or less at C., such as methane, ethane,

propane, ethylene,l or CO2 with liquids having i let above tank 26.

4 claims. icl. 21o-m) this mixture under pressure 'through a clarifyving filter unit of the Hele-Shaw type fitted for "kickback operation for cleaning. There is thus provided a commercially' feasible method of filtration adapted for the reclamation of crank case. and transformer oils or cleaners solvents such as naphtha, carbon tetrachloride, tri-chloroethylene, etc., and for general ltration.

In the accompanying drawings` which form part of the instant speciflcation and which are to be read in conjunction therewith: l

Figure 1 shows a schematic view of one form of apparatus capable of carrying out the process of my invention.A f l v FigureZ shows a schematic view of another form of apparatus capable of carrying outthe process of my invention.

More particularly referring now to the drawings and especially Figure 1, liquid propane, or

' anysuitable liqueiied normally gaseous diluent,

from tank I is forcedby the metering charge pump 2 through the line 3.- Similarly the viscous .liquid to be ltered is drawn fromtank 5 and forced `by charge pump 6 through the line 1, having a shut-od valve l, to the mixer ,4 where it is diluted with the propane. 'I'he diluted liquid is forced, under pressure, through the line 8 into the branch lines 9-|0 having shut-off valves lli2 controlling the input into the filter chambers i3 and I4. Hele-Shaw type filters l5 and i6 are mounted within chambers i3 and I4 respectively. Fastening means, not shown,- are provided to permit the removal of caps I5*il -and I6" witli their associated filter units from the chambers I3 and I4. Two-way valves I1 and IB are lprovided at the outlet of each ilter -and are interconnected through line lla. A line I9 leads from valve lto the evaporator tower 20'having` heating element 2l in the bottom thereof. A vapor discharge pipe 22 connects the tower 2u .with-condenser 23 and gas separator 24, the latreceiving tank 20.

Returning now to'thefllter chambers, a line 25 having a shut-oit valve 25n connects the viscous liquid feed line 'l with a treating slurry tank 2G.

A hopper 21 having a screw feed 28 or other equivalent mechanism is arranged with its out- When it is desired to use a solid treating agent in the system, the charge pump 29, connected to tank 26, furnishes a means for forcing the slurry of viscous material and ulation of the Valves 29a, 29", 29, and 23d. It is contemplated that the solid treating agent may I be thus introduced either intermittently or continuously. A branch line 3Q having a circulation pump 32 is connected between valves 23a and 29h, and discharges into the lower portion of chamber I3 at 38. A shut-oli valve 35 in line 34 controls the input into the chamber. Similar` ly, branch line 35vhaving pump 33 discharges into chamber I4 at 39 and is controlled by'valve 31. An auxiliary line 43 having shut-oi valves 4I, 42 connects lines 34 and 36 and is connected by line 43 with the iiash chamber 44 having a heating unit 45 and a removable bottom 3,48. A line 46 having shut-oi valve 51 connects the. upper portion of the flash chamber 34 with the line 22.

A line 48 having shut-off valve t8, connects the propane feed line 3 with the branch lines 50 and 5I, connected to the two-way valves Il and I8 respectively. An auxiliary line 52 having shut-ofi valve 52a interconnects the line 38 with the junction of lines 40 and 63.

Each chamber, I3 and I3, is provided with a baille 54 and 55 respectively, located within the chamber below the filter units I5 and I5 respectively. Heating units 52h and 53 are located in the bottoms of chambers I3 and I4 respectively.

The operation of the device is as follows. The liquefied diluent from tank I is mixed with the viscous liquid from tank 5 by the mixer 4 and fed into the chambers I3 and Id above the baiiies 54 and 55, through lines 3 and I0. The filtrate which passes through the units I5 and I6 is passed into tower 20 where the propane is evaporated by heating unit 2l and passes oii through line 22 to the condenser 23. This condensate after passing through gas separator 24 is returned to the tank I, thus completing the cycle. The solid material in the chambers I3 and I3 settles by gravity to the'bottom where it isl kept from caking by the constant circulation of slurry and treating agent (when agent is used) from tank 26, to which clay or other solid agent has been added from hopper 2I. A constant circulation of the slurry in the bottom of each chamber is maintained at all times through the action of pumps 32 and 33 withdrawing slurry from the bottom of each chamber and refeeding it at 38 and 39. In order that the operation of the units may be continuous, the valves 4| and 42 may be opened thus allowing a constant bleeding of the slurry circulating through the branches 30,34 and 30, 35. The slurry bled off through line 43 may be diluted by the addition of propane from line 52.' 'I'his serves to maintain the uidity of the slurry which passes into the flash chamber 44 through line 43. 'I'he heatingunit 55 and the pressure reduction in 44 serves to vaporize the propane in the slurry which passes off through line 46 to the condenser 23 where it is recovered for reuse. y

The caked slurry formed in the chamber 4t may be removed through the bottom of this chamber without shutting down the ltration units. Obviously, however, the bleeding through 43 may be dispensed with and the slurry in each tower I3, I4 permitted to cake and be removed through the bottom of each tower. The flltrate from each unit I5, I6 which has settled in tower 20 is drawn off through line 20a, treated in gas separator stripper 20, and the iinally treatediiltered material 1passed through pipe 20d to the collecting drum 20. 'I'he heating coils 52h, 53 in chambers 54., 55 serve to maintain the slurry in a liquid state while the baliles 5t, 55 prevent the turbulence caused by the recycling slurry in the bottom of the chamber from disturbing the quiet zone above the bailies.

The solid material which collects Aaround the lter units I5-I6 may be removed by the introduction of liquid propane, or nitrate, or gas, through the kick-back line 18.

Referring now to Figure 2, a mixture of viscous liquid and propane is fed into the chamber I through the line 2 by the pump 3. The filtrate passed bythe unit i is carried oli through the line 5 having a three-way valve 5El to an evaporator (not shown) where the propane is evaporated, condensed, and the liquid collected. IThe heavier component in the filter chamber is allowed to settle to the bottom of the chamber in a slurry-like liquid form. Time is not allowed for complete separation which would result in the formation of a cake or paste which could not be withdrawn without positive mechanical con' veyors. The partially separated slurry is transferred into the next chamber through the line Ii having a pump l. A portion of the slurry is recycled to thefllter chamber through a branch 3 having a shut-off valve 9. At the same time liquid propane is forced by pump I through line II, branch line I2, and shut-0E valve I3 in line I intol the slurry returning through line 3. The slurry is thus diluted and returned into the lter chamber below the baa I5 which preventsl the turbulence in the slurry from aiecting the quiet zone of filtration. Means may be provided for returning the slurry at any one of a plurality of points along the side of the chamber depending upon the zone of separation which may readily be determined by sampling at these points. 'I'he remainder of the slurry in line 6 passes through shut-off valve I6 and'is also diluted with liquid propane from line I2 which is connected through shut-01T valve II to the slurry line from valve I6. The diluted slurry is then fed into the chamber I8 where the process is repeated. A kick-back line I 3 is provided for feeding propane, or any suitable liquefied normally gaseous diluent, back through the -i'llter to remove at will the accumulated wax or other solid material from around the edges of the. iltr unit. Fox example, propane from line I9 is fed back through branch 20 and three-way valve 5, and line 5 into the top of the lter unit. 'I'he operation may be repeated in chamber |85.

It will be observed that the distinguishing characteristic of the process is the dilution of a viscous liquid by a liquid hydrocarbon, or other suitable low viscosity liquid, whereby a mixture of low viscosity is achieved and a resulting rapid filtration may be had with aA decanting clarifying lter of the Hele-Shaw type. It will be observed that I have accomplished the objects of -my invention. I am enabled to maintain a continuous operation of the system without the formation oi a cake or paste of slurry in the lter chambers thus avoiding the use of mechanical conveyors toremove the accumulated slurry.

It will be understood that certain features and' sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my' invention. It is,

therefore, to be understood that my invention is not to be limited to the 'specmc detalls shown and described.`

The'operation is particularly adapted to the filtration of crank case oils, transformer oils,

dry cleaners solvents, though it is to be understood that it may be used with various `ltering problems in general.

' Having thus described my invention, what If claim is: 1. A method of separating finely divided solid material from viscous liquids containing the same,

H comprising diluting the viscous liquid with a slurry removed from each zone is diluted with liquefied normally gaseousldiluent and a portion of each diluted slurry returned to the zone from which it was withdrawn.

3. A filtering apparatus including in combination a plurality of combined filtering and settling chambers, a capillary film filter unit in.

each chamber, baille means in each chamber below the filter units, means connecting the lower portion of successive chambers for. transferring liquid from one chamber to the succeeding chamber and for returning a portion of the liquid to the chamber from which it was withdrawn and means connected to said last named neans for adding a diluent to said liquid.

4. A filtering apparatus including in combination a plurality of filter chambers, a lter unit in each chamber, means connecting the lower portion of successive chambers for transferring liquid from one cham-ber to the succeeding chamber and for returning a portion of the liquid to the chamber from which it was withdrawn and means connected to said last named means for adding a diluent to said liquid.

EARL PE'I'I'Y..

2. A process as dened by claim 1 in which 

